Method of forming piston rings



J. REID.

METHOD OF FORMING PISTON RINGS. APPLICATION FILED MAR. 11, I920. RENEWEDJUNE 25,192L

. 1,405,332, Patent-ed Jan. 31,1922.

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J. REID.

METHOD OF FORMING PISTON RINGS.

APPLICATION FILED MAR. 11,1920. RENEWED JUNE 25,1921.

1,405,332; Patented, Jan. 31, 1922.

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UNITED STATES. PATENTTOFIFICE.

' JAMES REID, OF SYRACUSE, NEW YORK.

T 0 all whom it may concern:

, Be it known that I, JAMES REID, a citizen of the United States, residing at Syracuse, in the county of Onondaga and State of New York, have invented certain new and useful Improvements in Methods of FormingPiston Rings; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.-

The present invention relates to an improved method for forming piston rings, and consists in the steps hereinafter de scribed and claimed.

It is an object of the present invention to increase the elasticity and tension of piston rings and to produce this increased elasticity and tension uniformly throughout the rings.

It has always been desirable that piston rings made of cast iron be as elastic as possible and of an even or uniform tension in order to expand properly'and have the desired pressure and tight fit in the cylinder,

thus preventing the escape of gas or steam pastthe rings when in service This object has heretofore been accomplished in various .ways, all of which are attended with, difficulties and objections. One such method is to cast the ringblank so that the inner diameter as cast will be the exact size to fit in the groove in the piston, leaving the edges and outside diameter only to be machined, after which the joint is cut;

and in this case reliance for tension is placed entirely on the character of the metal for the probable expansion of the ring. This is by no means certain or reliable, as rings so made are found to vary widely in tension, and in many cases to possess very little, if any, tension, due to uncontrollable conditions existing probably in the mixture of iron and condition of casting, and therefore with this method a uniform product is impossible.

Another method heretofore proposed is to hammer harden the inner surface of the ring to impart stiffness. However, this method is costly and produces a ring of variable quality at best, as the effect of ham mer blows must necessarily be in spots.

A further method, which has also been in use, is to finish the one-piece ring all over and,'-after lap joint has been cut, to place the ring in a suitable fi'xture to hold it While a special device stamps a predetermined '11l1 in Figure 10.

Specification of Letters Patent. Patented J 31 1922 .Application filed March 11, 1920, Serial No. 364,988. Renewed June 25, 1921. l

Serial No. 00,464.

or prick points necessarily do not cover the entire inner suirace and therefore the tension is variable. The present invention aims to produce an improved method of treating one-piece pis- This method is open to ton rings which may be carried. out more cheaply and produce a elasticity in the ring. In the drawin Figure 1 is a' diagrammatic View of a oneuniform tension or piece ring showing the first step .in the process.

Figure 2 is a view of the second step, the lap joint.

Figure 3 is an edge view of the ring shown in Figure 2. Figure 4 is a plan view of the ring showing the third step in the process, with the lap joint closed.

Figure 5 is an edge view of the same. Figure 6 shows the ring in the open condition after it has been re-rolled and the outer planished surface removed.

Figure 7 is an edge view of the same. Figure 8 is a fragmentary sectional view of the ring showing 'the two planished or condensed inner and outer surfaces Figure 9 is.a similar view showing the outer planishe-d surface removed.

Figure 10 is a plan view of a' modified form of the device; and

Figure 11 is a section taken the ring showing which consists in cutting on the line The present improved method is carried out by first cutting out a one-piece continuous ring 1 to over-sized dimensions and machining the ring on'all surfaces.

The over-sized ring 1 thus machined is placed in some such apparatus diagrammatically indicated in Figure 1. This ap-" paratus consists in an enlarged hardened" steel roller 2 provided in combination with two smaller hardened steel rollers 3 and 4.

The rollers 2, 3 and 4 are arranged with their "peripliei'ies spaced apart as indicated in Figure l, and arranged in triangular relation, the two smaller rollers 3 and 4 bein spaced to opposite sides of the center of the main roller 2. The upper main roller 2 is ment of the adapted to be driven, while the smaller rollers 3 and 4 may rotate idly, due to the moveplston ring 1 thereover.

The over-sized machined piston ring 1 is placed between the roller 2 and the rollers 3 and 4 in the manner shown in Figure 1, and the roller 2 is put in motion and placed under pressure. This pressure may be exerted preferably upon the two outer rollers 3 and 4 by screw pressure or other suitable means. The ring is thus subjected to this rolling action for a predetermined length of time and with a predetermined amount of pressure, and as a result both the inner and outer surfaces thereof will acquire highly planished and condensed surfaces, as indicated at 5 and 6 in Figure 8.

After suitable surfaces 5 and 6 have been acquired, the ring 1 is removed from the apparatus shown in Figure 1 and the lap joint is cut out as shown in Figures 2 and 3. This lap joint is preferably of a special t pe, more particularly set up in my copen ing application entitled piston rings, filed November 26, 1919, Serial No. 340,713. The lap joint 7 is so cut out that the jointwill be in the open condition shown in Figures 2 and 3.

The ring 1 is next put through a re-rolling process in the same apparatus as shown in Figure 1, which will roll it to a smaller diameter and lap the joint 7 as shown in Figures 4 and 5.

The blank or ring 1 is then held in a suitable fixture, and while closed to working diameter, as shown in Figure 9, wherein the planished or condensed surface shown at 6 in Figure 8 is removed and the soft cast iron is exposed on the outer surface, where the ring is intended to come in contact with the lnner wall of the cyl nder. The inner planished and hardened surface 5 is retained,

as also shown in Figure 9.

' The removal of the, outer planishedhardened surface 6 relieves the ring of the contractile stress that would otherwiseinhere in the ring if this surface 6 were left thereon,

and, moreover, this hardened surface 6 would react disastrously upon the inner wall of the cylinder; whereas the soft cast iron which is exposed by the removal of the surface 6 is well suited to reciprocate in contact with the cylinder wall.

The removal of the outer planished surface 6 leaves the inner planished and hardened surface 5 to exert an expanding spring action on the ring 1 which will cause .it to normally assume the condition .shown in Figures 6 and 7 where the joint 7 is shown to be sprung open and the ring in condition to be placed in a cylinder.

The tension and elasticity of a ring of this character is uniform by reason of the fact that the main roller 2, of the apparatus shown in Figure 1, may rotate uniformly in overssized pis contact with all parts of the inner surface of the ring and may communlcate thereto a uniform inner planished and hardened surface 5, which is not possible with hammer blows or stamping devices.

Moreover, the degree of the planishing of like treatment. Moreover, the method is an exceedingly cheap one.

Th inner planished and hardened surface 5 of the ring imparts a condition much like a tempered steel spring placed within the ring for expanding the same, and this spring effect will remain during the entire life of the ring. The heat imparted to the 'ring when in a gasolene engine, acts more quickly on the planished or condensed surface 5 on the inner side of the ring and contributes additional gain to the tension of the ring when in actual use.

Referring to Figures 10 and 11, there is here shown a slightly modified form of device for use where the inner surface only is to be planished, which is sometimes desirable. A chucking fixture 8 is used to hold the ring 9 and grips the same onits outer circumference. The chucking fixtureis provided with a recess 10 in which arelocated three rollers 11, 12 and 13, arranged in triangular formation and hearing at their inner ends on the shaft 14.

I have described preferred and'satisfactory processes, but obviously changes could be made in the herein described method and apparatus which could be used without de parting from the spirlt of my lnvention.

I claim: 1 1. The herein described method of forming piston rings which consists in cutting out an over-sized. one-piece rm machining the over-sized ring. on all sur aces,'rolling the ring on its inner and outer surfaces to planish and condense the same,-cutting a joint in the ring, tract the same and close the joint, and removing theouter planished and hardened surface, substantially as described.

2. The herein described method of forming piston rin s which consists in making an on ring, imparting to the inner and outer faces thereof planished and hardened surfaces, thereafter cutting a joint in the ring, subsequently rolling the ring to contract the same and close the joint, and

afterwards removing the" outer planished and hardened surface, substantially as de scribed. 'f Y 3. The improved method as herein described for forming piston rings which consists in producing an oversizedone-piece Mat 3 re-rolling the ring to conring, machining the same all over, imparting to the inner and outer faces of the ring highly planished and condensed surfaces, thereaftercutting an open joint in the rim and the closing of the open joint, and finally removing the outerplanished and condensed surface, leaving the inner planished and 'condensed surface to act as a steel spring for opening the ring, substantially as described.

4. The herein described method for treating piston rings which consists in producing an over-sized one-piece continuo'us ring, Inachining said.ring all over, rolling the inner and outer surfaces of the ring under pres;

' sure whereby to produce planished and condensed surfaces, cutting an open joint in the ring, re-rolling the ring to contra ct thesume and close the open joint, and removing, as by turning, the outer planished and condensed surface whereby to free the ring from the contractile effect of the outer surface and leave the ring to the ex anding action of the inner planished and condensed surface, substantially as described.

5. The herein described method of form,- ing and treating piston rings which consists in cutting out-an over-sized one-piece ring, machining the over-sized ring on its inner surface, rolling the ring on its inner surface to planish and condense the same, cutting a joint in the ring, and re-rolling the ring to contract the same and close the joint, sub-.

stantially as described.

" JAMES REID. 

